The firm, based in Carrickfergus, Northern Ireland, currently imports, packs and distributes rice, cereals, pulses, nuts and bakery ingredients, as well as its soup mix brand.
Invest Northern Ireland has granted the company £213,000 towards the factory build and the upgrading of machinery and equipment, to streamline its production process and increase efficiencies.
The specialist factory will lead to the creation of 13 jobs, a spokesman told Food Manufacture.
Philip Johnston, operations director, revealed that food safety was at the heart of the new delivery.
"Although our nut products were already packed using dedicated machinery and strict allergen controls within our existing site, we are always conscious of the concern over nut allergies, especially peanuts," he said.
"To remove potential cross contamination, we took the decision to invest in a new completely separate processing and warehousing plant, to provide even greater assurance to our consumers.
"I would like to thank Invest NI for its continued support throughout our journey so far."
John Hood, director of food and drink at Invest NI, added: "Buchanans is a well-established company, renowned for its quality, service, price and brand name.
"We have worked with it closely for many years, previously supporting its initial move to a 25,000 sq ft production facility at our Trooperslane Business Park in Carrickfergus."
Yesterday, Reading Scientific Services (RSSL) called for greater guidance on allergens to assist with firms’ plans to administer safe free-from products.